homemade or Costco Reverse Osmosis Watermaker

[Bill Roosa]

As I see it..

I'd absolutely positively need a water maker ifI'm on the hook for an extended period of time and therefore away from a source of potable water andIt never rains in that location andThere is no fresh water stream on the land nearby for me to tap into.While I have not done the research I suspect that I'd not be sailing in those kinds of places without knowing it first and I could adjust my sailing/water supply accordingly.I agree with Mr Gainer that your boat should have a water tank that is big enough to "get you through the dry spots" (across the ocean in his case). Rain water just increases my time on the hook with out "going into port". In effect making my fuel tank level the deciding factor to head for port and not my water tank level.As a civil engineer I see a water maker as a way to trade water tank size for fuel tank size. The cost=benefit analysis does not support having a water maker. However the cost-convenience analysis does as it is certainly more convenient to flip a switch and fill a fuel tank than mess around with a catchment system in a storm. Why you might even get wet doing such a silly thing!!!!

 

[Alex]

Engineering and engineer

I was trained as a maritime engineer but not specifically in the RO business. When I went to sea (years ago) we use the steam of the turbine engine to boil the water and condense into drinking water. The amount of energy and maintnenace needed to do so is very high. Either RO or heat, you'll need energy.Now suppose the Costso stuff works, how and where you get the energy from? At home the water pressure from the city water (about 30-50 psi) powers the RO. When at sea, you need something to pressurize the water thus energy. You would need to run the engine a lot to make enough water just for drinking. So you'll trade carrying water to carrying fuel or energy making equipment.Most small ocean crossing sailboat has very large tanks for water. You'll need more than one just in case of contamination. They usually has some means of collecting rain water from the sail or canopy and filtering to make it drinkable. Some even have condensing capability to collect dew over night.If you are serious in doing this stuff; invest in conservation, capacity and collection. You need a minimum budget of 2 gallons a day. Just simple math.Real "engineer" design a system as a whole not just one component.My $0.02

 

[Franklin]

speaking of catching rain

For those of us who have a loose footed main, anybody seen or have a good rain catching system? I was thinking maybe I could rig something that would attach to the lifelines between the bow and the mast with a drain line in the middle that ran directly into the tank. Obviously, one wouldn't put this out if it's really blowing out or under sail and seas are rough.

 

[sailortonyb Allied Mis]

when is it necessary?

While I never intend to travel to certain places, there are others that go to uninhabited islands in the south pacific and other areas where water is not readily available. I dont foresee myself needing a water maker at this time, since I mainly coastal cruise and carry 150 gals. If however, i was to cross an ocean, i wouldnt think of doing it without a water maker. 30 plus days are a lot of days if something should happen to your water tank or supply regardless of how large the tank was. A large tank could get you through the dry spots if nothing were to happen to it, like a rupture and then you will have to sift through the bilge water. And of course, it doesnt rain regularly in all parts of the world.

 

[Robert Gainer]

Alex, I use 1/2 gallon per man/day

Alex,Just for reference I have always used the number 1/2 gallon of water per man per day as my planning number. I also carry a lot of fruit juice, tinned soup that doesn’t need water and some soda. I use salt water for washing and some cooking to help stretch the fresh water supply. In the past I have carried most of the water in small containers to avoid having a large percentage of the water being lost if any one container leaks. I also add a large percentage to the crossing time to allow for problems or unexpected weather. I have not owned a boat large enough to carry 2 gallons per man per day on a trans-ocean trip. England for instance took 59 days (22 foot boat one man) on one trip and 31 days (27 foot boat 2 men) on another crossing. If you use 2 gallons per man per day on a 27 foot boat with two men and a 30 day crossing with 20 day reserve you will need 200 gallons of water. That’s a lot of water instead of 50 gallons at the very comfortable rate of 1/2 gallon per man/day.All the best,Robert Gainer

 

[NautiDuck]

Can this get any better?

"It seems to me that Columbus and others did not have water makers and they did fine for the most part."Geez, I love this stuff.Let's get rid of fiberglass, Coumbus didn't need that either.

 

[sailortonyb Allied Mis]

I'll bet if Columbus had a .........

I'll bet if Columbus had a Hunter 33 he would have needed a water maker. How could anyone possibly make this correlation. Also, my history grades were'nt all that great, but from what I remember, the early explorers didnt make it all that 'fine'. As a matter of fact, in ole Chris's day, most seamen knew the earth was round and not flat. The primary thing that kept them from wandering too far off was that they normally couldnt carry more than 4 weeks supply of food and water, not to mention cargo. This equates to 2 weeks out and 2 weeks back. Cant find the new world in 2 weeks. I believe that when Mr and Mrs Columbus's little boy, Chris, finally made it to the Carribean, they were about out of food and water. There were very few condemned prisoners on his ships. Most decided that they would rather hang than starve or die of thirst.

 

[RichH]

Sailortonyb -

thanks for the kudosActually for the past 35 years my professional side has involved me a lot in 'separation technology': RO, ultrafiltration, straight filtration engineering and its application (among other engineering/science). I view the Costco "RO" as a slick marketing ploy that uses RO membranes in an inappropriate way, selling the 'marketing strength' on the use of the word - "RO". The permeability of such membranes with such little trans-membrane pressure is kind of laughable especially when the actual 'pore size' (units in "Daltons" or Molecular Weight Cut Off) of these membranes used are nowhere close to the retention needed to the job of salt removal/rejection. Im with Robt Gainer .... get a BIG tank. KISS is *always* better. Rainwater .... too much bio-debris in it - should be filtered/processed before being sent to tankage. A simple sand bed filter is probably the minimum requirement after you catch the rainwater. One has to remember that each and every drop of rain needs a nucleation site on which to form ... and thats either atmospheric dust or airborne bacteria, etc. Atmospheric air is an extremely dirty substance.

 

[Ross]

RandyK, Columbus had mutiny and scurvy to deal

with. But with a home brewed water maker you are betting you life that you got it right. Wooden boats are still being built in America and they are sea worthy, but they will not tolerate the benign neglect/pernicious that fiberglass boats suffer and still bring their occupants home.

 

[Robert Gainer]

TonyB, it was a tough time back then

TonyBIn that time period ships traveled in groups. They would loss anywhere from 50 to 75 percent of the crew during a long trip. It wasn’t unusual that if three ships went out very often only one returned. But they could carry 6 months to a year of food and more then 4 months of water. Fresh food of course lasted for a much shorter time and salted or dried food wasn’t very popular so whenever they could they would re-supply. To stretch the fresh food out they also carried goats, pigs etc for fresh food.The educated know the world was round and in fact the Greeks calculated the diameter within a few thousand miles hundreds of years before Europe even accepted the idea of a round earth.All the best,Robert Gainer

 

[NautiDuck]

Ross, I love wooden boats

Just wouldn't want to be responsible for one! As for mutiny, well the Admiral has been close on a couple of occasions. Scurvy? None of your business. ;-)

 

[tom]

Neat Water Catcher

I saw a nice boat that had a hard Bimini and they had a rail around the edges of the bimini to catch water. There was a drain hole connected to tubing that they could run to the tanks. They would let it rain enough to wash off the poop and salt then run the water through a filter into their tanks. If they were really low they would catch the first water to use for showers etc. They had tankage for a couple of weeks and a good shower or two would provide many gallons. At some point I plan to build a hard bimini and have a simular system. My foredeck drains throgh two scuppers that have hoses that could be used to collect water. Deck water would be fine for washing clothes and even drinking when in a survival mode. RO would be great to have but initial cost, maintenance and energy would make it expensive water.

 

[Ken]

Franklin

Check out the latest issue of Good Old Boat Jan/Feb 2007 I think you'll find the answers there. Several other ways discussed to catch water as well.

 

[r.w.landau]

Boy, you guys sure like to beat people up.

I like people like Moody that stay objective (he is not the only one), Some of you other guys are like dogs peeing on a tree to claim it. If you didn't understand that, you are trying to show what you know instead of helping people. Letterman had what he thought was a good idea. He asked not to be beaten up and you guys did your best not only to beat him up but to insult him. Recently Phil made a comment about how he is sometimes ashamed of the way some posters are treated. For those who trashed, beware, it may come back around...I would say that out of the threads that are running, few have stayed on the "help the poster who asked the question".Letterman, thanks for being dog meat, no one will ask that question for a while...r.w.landau

 

[sailortonyb Allied Mis]

Robert Gainer............

Thanks for the bit of history update. History was not a favorite subject of mine when in school, now however, I find myself glued to The HISTORY CHANNEL at times. BTW, are we done beating eachother up on the other post?Anyway, I used to live in Newburgh, on the other side of the Hudson. Always said that the Hudson Valley is one of the prettiest places in the US. Tony B

 

[Terry Cox]

When Karen Thorndike did her solo...

circumnavigation on Amelia, a 36 foot cutter, it had one 32 gallon water tank. She told me that it was enough for her needs between her eight ports of call. Her longest distance between ports was 93 days.Terry

 

[Robert Gainer]

Tony B

Tony B,Newburgh is OK but Beacon is quite the up and coming place now. As you say the Hudson Valley is beautiful and it’s hard to imagine a better place to home port a boat.I think the other thread has run its course now. But if you miss the fun we can start up again on another thread. This time you get to pick it. Just let me know where and when to start. You know I am just kidding don’t you.All the best,Robert Gainer

 

[Robert Gainer]

Karen Thorndike using less then 4/10 gallon a day

Wow, I thought I had a tight budget for water. I use 1/2 gallon per man/day but Karen Thorndike is using less then 4/10 of a gallon per day. I wonder if she caries much fruit juice and soda onboard. What do other people use as a number for fresh water use?All the best,Robert Gainer

 

[Ross]

Robert G. Maybe she is smaller than you

that can make a difference. But that still seems like a pretty dry crossing. If the weather was cool that could make a difference. I have gone through a gallon of water in one day and still lost weight. Physical labor and upper 90's.

 

[Wanderer138]

Daily water usage rates

The number I recall seeing was about one gallon per person per day in the tropics. I can easily consume a gallon a day in a typical Florida summer and about half that in the winter. However, since I'm usually on short hops, supply is not an issue.Location and time of year make a huge difference in availability of rainwater. For example, the windward (usually eastern) side of most mountainous Caribbean islands is usually rainy while islands at lower elevation (like Antigua, the Bahamas, Turks and Caicos) and the leeward sides of mountainous islands are drier. Caribbean summers are usually rainy and the winters are usually dry.Even with today's polluted air, rainwater is still a good source of potable water. Give it about ten miutes to wash the salt off the deck and sails and go for it. I've been on boats where they hung the sailcover upside down under the boom and others where they used a wet towel to dam the water running off the deck and direct it into the deck fill for the water tank. Add a couple of drops of bleach to the tank and you'll be fine. If you're concerned about bird crap, go out and swab the deck when the rain first starts. You'll get a nice frashwater shower in the bargain.PeterH23 "Raven"